1. Field of the Invention
The present invention relates to an image encoding apparatus, an image encoding method, an image encoding program, an image decoding apparatus, an image decoding method, and an image decoding program.
2. Related Background of the Invention
In recent years, due to a wide spread of internet, transmission and reception of image data or storing of image data have been widely conducted via a network. Generally, a lossy coding system capable of efficiently reducing the volume of image data is used for image data encoding. An H.264 video encoding system, which is an international standard recommended by the ITU-T (for example, ITU-T VCEG (Q.6/16), “H.26L Test Model Long Term Number 8 (TML-8) draft0”) is an example of the lossy coding system.
In the intra coding frame (I frame) of H.264, video compression is performed by intra-frame coding using Intra prediction. Further, in the inter-frame coding of H.264, the coding target frame is divided, for example, in macroblocks with a size of 16 ×16 pixels and the encoding is then performed for each macroblock. The macroblocks are further divided into blocks with a size of 16×8 pixels or 8×8 pixels and the motion compensation prediction is performed for each divided block. As a result, the redundancy of the video in the time direction is reduced.